It’s actually a part of a larger campaign — the poster being the least impressive part of it. Two major daily newspapers (“Gazeta Wyborcza” and “Rzeczpospolita”) had their front pages printed as if they were masked with black marker (used by the censorship in Belarus). You can see the front page of “Wyborcza” here:http://bi.gazeta.pl/im/3/3028/z3028343G.jpg